//
// VMime library (http://www.vmime.org)
// Copyright (C) 2002 Vincent Richard <vincent@vmime.org>
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 3 of
// the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// Linking this library statically or dynamically with other modules is making
// a combined work based on this library.  Thus, the terms and conditions of
// the GNU General Public License cover the whole combination.
//

#include <iomanip>

#include "vmime/config.hpp"
#include "vmime/dateTime.hpp"
#include "vmime/platform.hpp"
#include "vmime/parserHelpers.hpp"

#include "vmime/utility/datetimeUtils.hpp"


namespace vmime {

/*

 RFC #822:
 5. DATE AND TIME SPECIFICATION

date-time = [ day "," ] date time                 ; dd mm yy
                                                  ; hh:mm:ss zzz
day = "Mon" / "Tue" / "Wed" / "Thu" /
      "Fri" / "Sat" / "Sun"

date = 1*2DIGIT month 2DIGIT                      ; day month year
                                                  ; e.g. 20 Jun 82
month = "Jan" / "Feb" / "Mar" / "Apr" /
        "May" / "Jun" / "Jul" / "Aug" /
        "Sep" / "Oct" / "Nov" / "Dec"

time = hour zone                                  ; ANSI and Military

hour = 2DIGIT ":" 2DIGIT [":" 2DIGIT]             ; 00:00:00 - 23:59:59

zone = "UT" / "GMT"                               ; Universal Time
                                                  ; North American : UT
       / "EST" / "EDT"                            ; Eastern: - 5/ - 4
       / "CST" / "CDT"                            ; Central: - 6/ - 5
       / "MST" / "MDT"                            ; Mountain: - 7/ - 6
       / "PST" / "PDT"                            ; Pacific: - 8/ - 7
       / 1ALPHA                                   ; Military: Z = UT;
                                                  ; A:-1; (J not used)
                                                  ; M:-12; N:+1; Y:+12
       / ( ("+" / "-") 4DIGIT )                   ; Local differential
                                                  ; hours+min. (HHMM)
*/


void datetime::parseImpl(
	const parsingContext& /* ctx */,
	const string& buffer,
	const size_t position,
	const size_t end,
	size_t* newPosition
) {

	const char* const pend = buffer.data() + end;
	const char* p = buffer.data() + position;

	// Parse the date and time value
	while (p < pend && parserHelpers::isSpace(*p)) ++p;

	if (p < pend) {

		if (parserHelpers::isAlpha(*p)) {

			// Ignore week day
			while (p < pend && parserHelpers::isAlpha(*p)) ++p;
			while (p < pend && parserHelpers::isSpace(*p)) ++p;
			if (p < pend && *p == ',') ++p;
			while (p < pend && parserHelpers::isSpace(*p)) ++p;
		}

		bool dayParsed = false;

		if (parserHelpers::isAlpha(*p)) {

			// Ill-formed date/time, this may be the month,
			// so we skip day parsing (will be done later)

		} else {

			while (p < pend && !parserHelpers::isDigit(*p)) ++p;

			if (p < pend && parserHelpers::isDigit(*p)) {

				// Month day
				int day = 0;

				do {
					day = day * 10 + (*p - '0');
					++p;
				} while (p < pend && parserHelpers::isDigit(*p));

				m_day = (day >= 1 && day <= 31) ? day : 1;

				while (p < pend && !parserHelpers::isSpace(*p)) ++p;
				while (p < pend && parserHelpers::isSpace(*p)) ++p;

			} else {

				m_day = 1;

				// Skip everything to the next field
				while (p < pend && !parserHelpers::isSpace(*p)) ++p;
				while (p < pend && parserHelpers::isSpace(*p)) ++p;
			}

			dayParsed = true;
		}

		if (p < pend && parserHelpers::isAlpha(*p)) {

			// Month
			char_t month[4] = { 0 };
			int monthLength = 0;

			do {
				month[monthLength++] = *p;
				++p;
			} while (monthLength < 3 && p < pend && parserHelpers::isAlpha(*p));

			while (p < pend && parserHelpers::isAlpha(*p)) ++p;

			switch (month[0]) {

				case 'a':
				case 'A': {

					if (month[1] == 'u' || month[1] == 'U')
						m_month = AUGUST;
					else
						m_month = APRIL; // by default

					break;
				}
				case 'd':
				case 'D': {

					m_month = DECEMBER;
					break;
				}
				case 'f':
				case 'F': {

					m_month = FEBRUARY;
					break;
				}
				case 'j':
				case 'J': {

					if (month[1] == 'u' || month[1] == 'U') {

						if (month[2] == 'l' || month[2] == 'L') {
							m_month = JULY;
						} else {  // if (month[2] == 'n' || month[2] == 'N')
							m_month = JUNE;
						}

					} else {

						m_month = JANUARY; // by default
					}

					break;
				}
				case 'm':
				case 'M': {

					if ((month[1] == 'a' || month[1] == 'A') &&
					    (month[2] == 'y' || month[2] == 'Y')) {

						m_month = MAY;

					} else {

						m_month = MARCH; // by default
					}

					break;
				}
				case 'n':
				case 'N': {

					m_month = NOVEMBER;
					break;
				}
				case 'o':
				case 'O': {

					m_month = OCTOBER;
					break;
				}
				case 's':
				case 'S': {

					m_month = SEPTEMBER;
					break;
				}
				default: {

					m_month = JANUARY; // by default
					break;
				}
			}

			while (p < pend && !parserHelpers::isSpace(*p)) ++p;
			while (p < pend && parserHelpers::isSpace(*p)) ++p;

		} else {

			m_month = JANUARY;

			if (parserHelpers::isDigit(*p)) {

				// Here, we expected a month, but it maybe
				// a ill-formed date, so try to parse a year
				// (we don't skip anything).

			} else {

				// Skip everything to the next field
				while (p < pend && !parserHelpers::isSpace(*p)) ++p;
				while (p < pend && parserHelpers::isSpace(*p)) ++p;
			}
		}

		if (!dayParsed && p < pend && parserHelpers::isDigit(*p)) {

			// Month day
			int day = 0;

			do {
				day = day * 10 + (*p - '0');
				++p;
			} while (p < pend && parserHelpers::isDigit(*p));

			m_day = (day >= 1 && day <= 31) ? day : 1;

			while (p < pend && !parserHelpers::isSpace(*p)) ++p;
			while (p < pend && parserHelpers::isSpace(*p)) ++p;
		}

		if (p < pend && parserHelpers::isDigit(*p)) {

			// Check for ill-formed date/time and try to recover
			if (p + 2 < pend && *(p + 2) == ':') {

				// Skip year (default to current), and advance
				// to time parsing
				m_year = now().getYear();

			} else {

				// Year
				int year = 0;

				do {
					year = year * 10 + (*p - '0');
					++p;
				} while (p < pend && parserHelpers::isDigit(*p));

				if (year < 70)         m_year = year + 2000;
				else if (year < 1000)  m_year = year + 1900;
				else                   m_year = year;

				while (p < pend && !parserHelpers::isSpace(*p)) ++p;
				while (p < pend && parserHelpers::isSpace(*p)) ++p;
			}

		} else {

			m_year = 1970;

			// Skip everything to the next field
			while (p < pend && !parserHelpers::isSpace(*p)) ++p;
			while (p < pend && parserHelpers::isSpace(*p)) ++p;
		}

		if (p < pend && parserHelpers::isDigit(*p)) {

			// Hour
			int hour = 0;

			do {
				hour = hour * 10 + (*p - '0');
				++p;
			} while (p < pend && parserHelpers::isDigit(*p));

			m_hour = (hour >= 0 && hour <= 23) ? hour : 0;

			while (p < pend && parserHelpers::isSpace(*p)) ++p;

			if (p < pend && *p == ':') {

				++p;

				while (p < pend && parserHelpers::isSpace(*p)) ++p;

				if (p < pend && parserHelpers::isDigit(*p)) {

					// Minute
					int minute = 0;

					do {
						minute = minute * 10 + (*p - '0');
						++p;
					} while (p < pend && parserHelpers::isDigit(*p));

					m_minute = (minute >= 0 && minute <= 59) ? minute : 0;

					while (p < pend && parserHelpers::isSpace(*p)) ++p;

					if (p < pend && *p == ':') {

						++p;

						while (p < pend && parserHelpers::isSpace(*p)) ++p;

						if (p < pend && parserHelpers::isDigit(*p)) {

							// Second
							int second = 0;

							do {
								second = second * 10 + (*p - '0');
								++p;
							} while (p < pend && parserHelpers::isDigit(*p));

							m_second = (second >= 0 && second <= 59) ? second : 0;

							while (p < pend && !parserHelpers::isSpace(*p)) ++p;
							while (p < pend && parserHelpers::isSpace(*p)) ++p;

						} else {

							m_second = 0;
						}

					} else {

						m_second = 0;
					}

				} else {

					m_minute = 0;
				}

			} else {

				m_minute = 0;
			}

		} else {

			m_hour = 0;

			// Skip everything to the next field
			while (p < pend && !parserHelpers::isSpace(*p)) ++p;
			while (p < pend && parserHelpers::isSpace(*p)) ++p;
		}

		if (p + 1 < pend && (*p == '+' || *p == '-') && parserHelpers::isDigit(*(p + 1))) {

			const char_t sign = *p;
			++p;

			// Zone offset (in hour/minutes)
			int offset = 0;

			do {
				offset = offset * 10 + (*p - '0');
				++p;
			} while (p < pend && parserHelpers::isDigit(*p));

			const int hourOff = offset / 100;
			const int minOff = offset % 100;

			if (sign == '+') {
				m_zone = hourOff * 60 + minOff;
			} else {
				m_zone = -(hourOff * 60 + minOff);
			}

		} else if (p < pend && isalpha(*p)) {

			bool done = false;

			// Zone offset (Time zone name)
			char_t zone[4] = { 0 };
			int zoneLength = 0;

			do {
				zone[zoneLength++] = *p;
				++p;
			} while (zoneLength < 3 && p < pend);

			switch (zone[0])
			{
			case 'c':
			case 'C':
			{
				if (zoneLength >= 2)
				{
					if (zone[1] == 's' || zone[1] == 'S')
						m_zone = CST;
					else
						m_zone = CDT;

					done = true;
				}

				break;
			}
			case 'e':
			case 'E':
			{
				if (zoneLength >= 2) {

					if (zone[1] == 's' || zone[1] == 'S') {
						m_zone = EST;
					} else {
						m_zone = EDT;
					}

					done = true;
				}

				break;
			}
			case 'm':
			case 'M': {

				if (zoneLength >= 2) {

					if (zone[1] == 's' || zone[1] == 'S') {
						m_zone = MST;
					} else {
						m_zone = MDT;
					}

					done = true;
				}

				break;
			}
			case 'p':
			case 'P': {

				if (zoneLength >= 2) {

					if (zone[1] == 's' || zone[1] == 'S') {
						m_zone = PST;
					} else {
						m_zone = PDT;
					}

					done = true;
				}

				break;
			}
			case 'g':
			case 'G':
			case 'u':
			case 'U': {

				if (zoneLength >= 2) {

					m_zone = GMT;  // = UTC
					done = true;
				}

				break;
			}

			}

			if (!done) {

				const char_t z = zone[0];

				// Military time zone
				if (z != 'j' && z != 'J') {

					typedef std::map <char_t, int> Map;
					static const Map::value_type offsetMapInit[] = {

						Map::value_type('a', -60),
						Map::value_type('b', -120),
						Map::value_type('c', -180),
						Map::value_type('d', -240),
						Map::value_type('e', -300),
						Map::value_type('f', -360),
						Map::value_type('g', -420),
						Map::value_type('h', -480),
						Map::value_type('i', -540),
						Map::value_type('k', -600),
						Map::value_type('l', -660),
						Map::value_type('m', -720),

						Map::value_type('n', 60),
						Map::value_type('o', 120),
						Map::value_type('p', 180),
						Map::value_type('q', 240),
						Map::value_type('r', 300),
						Map::value_type('s', 360),
						Map::value_type('t', 420),
						Map::value_type('u', 480),
						Map::value_type('v', 540),
						Map::value_type('w', 600),
						Map::value_type('x', 660),
						Map::value_type('y', 720),

						Map::value_type('z', 0),
					};

					static const Map offsetMap(
						::vmime::begin(offsetMapInit),
						::vmime::end(offsetMapInit)
					);

					Map::const_iterator pos =
						offsetMap.find(parserHelpers::toLower(z));

					if (pos != offsetMap.end()) {
						m_zone = (*pos).second;
					} else {
						m_zone = GMT;
					}

				} else {

					m_zone = GMT;
				}
			}

		} else {

			m_zone = 0;
		}

	} else {

		m_year = 1970;
		m_month = JANUARY;
		m_day = 1;

		m_hour = 0;
		m_minute = 0;
		m_second = 0;

		m_zone = 0;
	}

	setParsedBounds(position, end);

	if (newPosition) {
		*newPosition = end;
	}
}


void datetime::generateImpl(
	const generationContext& /* ctx */,
	utility::outputStream& os,
	const size_t curLinePos,
	size_t* newLinePos
) const {

	static const char* dayNames[] = {
		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
	};
	static const char* monthNames[] = {
		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
	};

	const int z = ((m_zone < 0) ? -m_zone : m_zone);
	const int zh = z / 60;
	const int zm = z % 60;

	std::ostringstream oss;
	oss.imbue(std::locale::classic());

	oss << dayNames[getWeekDay()] << ", "
	    << m_day << " " << monthNames[m_month - 1] << " " << m_year
	    << " " << std::setfill('0') << std::setw(2) << m_hour << ":"
	    << std::setfill('0') << std::setw(2) << m_minute << ":"
	    << std::setfill('0') << std::setw(2) << m_second
	    << " " << ((m_zone < 0) ? '-' : '+') << std::setfill('0') << std::setw(2) << zh
	    << std::setfill('0') << std::setw(2) << zm;

	const string& str = oss.str();
	os << str;

	if (newLinePos) {
		*newLinePos = curLinePos + str.length();
	}
}


datetime::datetime()
	: m_year(1970), m_month(1), m_day(1),
	  m_hour(0), m_minute(0), m_second(0), m_zone(0) {

}


datetime::datetime(const int year, const int month, const int day)
	: m_year(year), m_month(month), m_day(day),
	  m_hour(0), m_minute(0), m_second(0), m_zone(0) {

}


datetime::datetime(
	const int year,
	const int month,
	const int day,
	const int hour,
	const int minute,
	const int second,
	const int zone
)
	: m_year(year),
	  m_month(month),
	  m_day(day),
	  m_hour(hour),
	  m_minute(minute),
	  m_second(second),
	  m_zone(zone) {

}


datetime::datetime(const datetime& d)
	: headerFieldValue(),
	  m_year(d.m_year),
	  m_month(d.m_month),
	  m_day(d.m_day),
	  m_hour(d.m_hour),
	  m_minute(d.m_minute),
	  m_second(d.m_second),
	  m_zone(d.m_zone) {

}


datetime::datetime(const time_t t, const int zone) {

#if VMIME_HAVE_LOCALTIME_S

	struct tm tms;

	if (!gmtime_s(&tms, &t)) {
		localtime_s(&tms, &t);
	}

#elif VMIME_HAVE_LOCALTIME_R
	struct tm tms;

	if (!gmtime_r(&t, &tms)) {
		localtime_r(&t, &tms);
	}

#else

	struct tm* gtm = gmtime(&t);
	struct tm* ltm = localtime(&t);

	struct tm tms;

	if (gtm) {
		tms = *gtm;
	} else if (ltm) {
		tms = *ltm;
	}

#endif

	m_year = tms.tm_year + 1900;
	m_month = tms.tm_mon + 1;
	m_day = tms.tm_mday;
	m_hour = tms.tm_hour;
	m_minute = tms.tm_min;
	m_second = tms.tm_sec;
	m_zone = zone;
}


datetime::datetime(const string& date) {

	parse(date);
}


datetime::~datetime() {

}


void datetime::copyFrom(const component& other) {

	const datetime& d = dynamic_cast <const datetime&>(other);

	m_year = d.m_year;
	m_month = d.m_month;
	m_day = d.m_day;
	m_hour = d.m_hour;
	m_minute = d.m_minute;
	m_second = d.m_second;
	m_zone = d.m_zone;
}


datetime& datetime::operator=(const datetime& other) {

	copyFrom(other);
	return *this;
}


datetime& datetime::operator=(const string& s) {

	parse(s);
	return *this;
}


void datetime::getTime(int& hour, int& minute, int& second, int& zone) const {

	hour = m_hour;
	minute = m_minute;
	second = m_second;
	zone = m_zone;
}


void datetime::getTime(int& hour, int& minute, int& second) const {

	hour = m_hour;
	minute = m_minute;
	second = m_second;
}


void datetime::getDate(int& year, int& month, int& day) const {

	year = m_year;
	month = m_month;
	day = m_day;
}


void datetime::setTime(
	const int hour,
	const int minute,
	const int second,
	const int zone
) {

	m_hour = hour;
	m_minute = minute;
	m_second = second;
	m_zone = zone;
}


void datetime::setDate(
	const int year,
	const int month,
	const int day
) {

	m_year = year;
	m_month = month;
	m_day = day;
}


const datetime datetime::now() {

	return platform::getHandler()->getCurrentLocalTime();
}


shared_ptr <component> datetime::clone() const {

	return make_shared <datetime>(*this);
}


const std::vector <shared_ptr <component> > datetime::getChildComponents() {

	return std::vector <shared_ptr <component> >();
}


int datetime::getYear() const { return m_year; }
int datetime::getMonth() const { return m_month; }
int datetime::getDay() const { return m_day; }
int datetime::getHour() const { return m_hour; }
int datetime::getMinute() const { return m_minute; }
int datetime::getSecond() const { return m_second; }
int datetime::getZone() const { return m_zone; }
int datetime::getWeekDay() const { return utility::datetimeUtils::getDayOfWeek(m_year, m_month, m_day); }
int datetime::getWeek() const { return utility::datetimeUtils::getWeekOfYear(m_year, m_month, m_day); }

void datetime::setYear(const int year) { m_year = year; }
void datetime::setMonth(const int month) { m_month = std::min(std::max(month, 1), 12); }
void datetime::setDay(const int day) { m_day = day; }
void datetime::setHour(const int hour) { m_hour = hour; }
void datetime::setMinute(const int minute) { m_minute = minute; }
void datetime::setSecond(const int second) { m_second = second; }
void datetime::setZone(const int zone) { m_zone = zone; }


bool datetime::operator==(const datetime& other) const {

	const datetime ut1 = utility::datetimeUtils::toUniversalTime(*this);
	const datetime ut2 = utility::datetimeUtils::toUniversalTime(other);

	return ut1.m_year   == ut2.m_year   &&
	       ut1.m_month  == ut2.m_month  &&
	       ut1.m_day    == ut2.m_day    &&
	       ut1.m_hour   == ut2.m_hour   &&
	       ut1.m_minute == ut2.m_minute &&
	       ut1.m_second == ut2.m_second;
}


bool datetime::operator!=(const datetime& other) const {

	const datetime ut1 = utility::datetimeUtils::toUniversalTime(*this);
	const datetime ut2 = utility::datetimeUtils::toUniversalTime(other);

	return ut1.m_year   != ut2.m_year   ||
	       ut1.m_month  != ut2.m_month  ||
	       ut1.m_day    != ut2.m_day    ||
	       ut1.m_hour   != ut2.m_hour   ||
	       ut1.m_minute != ut2.m_minute ||
	       ut1.m_second != ut2.m_second;
}


bool datetime::operator<(const datetime& other) const {

	const datetime ut1 = utility::datetimeUtils::toUniversalTime(*this);
	const datetime ut2 = utility::datetimeUtils::toUniversalTime(other);

	return (ut1.m_year    <  ut2.m_year) ||
	       ((ut1.m_year   == ut2.m_year)   && ((ut1.m_month  < ut2.m_month)  ||
	       ((ut1.m_month  == ut2.m_month)  && ((ut1.m_day    < ut2.m_day)    ||
	       ((ut1.m_day    == ut2.m_day)    && ((ut1.m_hour   < ut2.m_hour)   ||
	       ((ut1.m_hour   == ut2.m_hour)   && ((ut1.m_minute < ut2.m_minute) ||
	       ((ut1.m_minute == ut2.m_minute) && ((ut1.m_second < ut2.m_second)))))))))));
}


bool datetime::operator<=(const datetime& other) const {

	const datetime ut1 = utility::datetimeUtils::toUniversalTime(*this);
	const datetime ut2 = utility::datetimeUtils::toUniversalTime(other);

	return (ut1.m_year    <  ut2.m_year) ||
	       ((ut1.m_year   == ut2.m_year)   && ((ut1.m_month  <  ut2.m_month)  ||
	       ((ut1.m_month  == ut2.m_month)  && ((ut1.m_day    <  ut2.m_day)    ||
	       ((ut1.m_day    == ut2.m_day)    && ((ut1.m_hour   <  ut2.m_hour)   ||
	       ((ut1.m_hour   == ut2.m_hour)   && ((ut1.m_minute <  ut2.m_minute) ||
	       ((ut1.m_minute == ut2.m_minute) && ((ut1.m_second <= ut2.m_second)))))))))));
}


bool datetime::operator>(const datetime& other) const {

	const datetime ut1 = utility::datetimeUtils::toUniversalTime(*this);
	const datetime ut2 = utility::datetimeUtils::toUniversalTime(other);

	return (ut1.m_year    >  ut2.m_year) ||
	       ((ut1.m_year   == ut2.m_year)   && ((ut1.m_month  > ut2.m_month)  ||
	       ((ut1.m_month  == ut2.m_month)  && ((ut1.m_day    > ut2.m_day)    ||
	       ((ut1.m_day    == ut2.m_day)    && ((ut1.m_hour   > ut2.m_hour)   ||
	       ((ut1.m_hour   == ut2.m_hour)   && ((ut1.m_minute > ut2.m_minute) ||
	       ((ut1.m_minute == ut2.m_minute) && (ut1.m_second > ut2.m_second))))))))));
}


bool datetime::operator>=(const datetime& other) const {

	const datetime ut1 = utility::datetimeUtils::toUniversalTime(*this);
	const datetime ut2 = utility::datetimeUtils::toUniversalTime(other);

	return (ut1.m_year    >  ut2.m_year) ||
	       ((ut1.m_year   == ut2.m_year)   && ((ut1.m_month  >  ut2.m_month)  ||
	       ((ut1.m_month  == ut2.m_month)  && ((ut1.m_day    >  ut2.m_day)    ||
	       ((ut1.m_day    == ut2.m_day)    && ((ut1.m_hour   >  ut2.m_hour)   ||
	       ((ut1.m_hour   == ut2.m_hour)   && ((ut1.m_minute >  ut2.m_minute) ||
	       ((ut1.m_minute == ut2.m_minute) && (ut1.m_second >= ut2.m_second))))))))));
}


} // vmime
